Design and implementation of parking spaces monitoring  system based on MMC21xMG

JIN Hua-qiang1， ZHANG You-bing1， XIA Xiao-gen2
（1. College of Information Engineering， Zhejiang University of Technology， Hangzhou 310023， China；
2. Shuyu Technology （Hangzhou）Co. Ltd.， Hangzhou 310007， China）

Abstract： Aiming at the growing problem of “difficult parking” and the increasing demand for the parking spaces testing in the city ，a parking spaces monitoring system based on the anisotropic magnetoresistive （AMR） sensors MMC21xMG was designed. The program was based on the principle that the vehicles on the parking spaces affect the distribution of the magnetic field surrounding. Combined with wireless technology， the high sensitivity anisotropic magnetoresistive sensors MMC21xMG was chosen to detect changes  in the geomagnetic field accurately in real time. The design of the hardware and software was given in detail. The hardware of the system was consisted of detection module，communication module and the server，the software of the system was consisted of testing program，communication program，and server program. The output of the system under different environmental were tested and a threshold algorithm was presented to determine whether there were vehicles based on the multiple sets of data obtained. Using the algorithm，the system were evaluated. The application results show that the detection accuracy is higher than 95%. The experimental results show that the system is feasible and efficient，the implementation cost is low，and has a wide range of applications，it could be widely used．
Key words： anisotropic magnetoresistive （AMR） sensors；parking spaces monitoring；ATmega48；MMC212xMG；SX1212